A+T 500 series Wind Sensors - highest accuracy and faster response
by Mark Jardine 9 Feb 04:00 PST
A+T 500 series Wind Sensor © A+T Instruments
A+T Instruments may be a name that needs introducing to you in the world of performance marine instrumentation. They are a group of highly qualified engineers who are taking a no-compromise approach to designing and constructing the best sensors and instruments on the market.
A+T have gained a strong reputation in the superyacht and high-end race yacht sector, but their products are just as applicable for all sectors of the yachting market, and can provide you with the competitive edge to win races.
Today we're taking a look at the A+T 500 series Wind Sensors, which offer the highest accuracy and fastest response available. Every single aspect of the design has been studied to understand what makes for the best wind sensor, and how to deliver that information to sailors, be that using their existing processors and displays, or using A+T's own market-leading options.
Providing your marine processor and display with accurate wind data is essential as so many calculations are based on what is being provided by your wind sensor.
Let's make the analogy with a classic hi-fi system: if the needle and tonearm on a record player are of poor quality, then the resulting signal sent to any high-quality speakers will just be an amplified version and subsequently sound terrible.
Well-designed quality sensors are essential to getting accurate data on your displays. So, how have A+T achieved this? Let's look at the main points, working from the top. Sorry if this gets a bit technical, but it's these details which all contribute to the accuracy of the A+T 500 series Wind Sensors:
- The vane has a high aspect ratio, with as little as possible of the main body in front of the vane, to ensure smooth and clear airflow.
- The vane is made of carbon to keep it light and give it a faster response, with the user adjustable counterbalance kept deliberately stubby to reduce its moment of inertia*, allowing it to rotate easily.
- The electronics inside the windvane consist of a coil with a sloping ring, sending the circuit board a signal indicating the direction the windvane is pointing. This measurement is analogue, and no two coils are exactly the same. So the board is put into a calibration rig, and stepped around in 4,800 increments to complete a full circle, creating a look up table which is stored on an EPROM** on the circuit board. This is what gives the vane the extraordinary 0.2 degrees accuracy.
- The body of the windvane is graphite infused, which (due to its conducting nature) reduces the risk of damage due to static and storms. It's also stronger than plastic, which has become more and more important as the shock loads at the top of the mast increase on modern yachts.
- The bearings on the vane and cups are ceramic, which give better performance, particularly at low wind speeds, and are corrosion resistant.
Importantly the A+T 500 series Wind Sensors are compatible with existing systems, so you can replace like-for-like to improve the accuracy of your wind readings straight away.
All parts and spares are held in stock, so if something does break, you don't have to replace the whole unit, just the part. These parts can in many cases be fitted to existing wands saving money and the environment.
We'll be taking a look at other A+T Instruments throughout the year, but wanted to start from the top, and cover the most important sensor. You can contact the team at A+T here.
* Moment of Inertia is expressed as I = Mr², where M is the mass and r is the distance from the axis of rotation.
** EPROM (Erasable Programmable Read-Only Memory), is a type of programmable chip that retains its data when its power supply is switched off.